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Go with the 2012 all the way, if you want to upgrade RAM or add second drive at a later date.

The lack of user-upgradable RAM is ridiculous - I'm definitely going for the older model now. Wish I'd bought the 2012 I saw on the refurb store yesterday - kicking myself now!
 
There is no way in hell people should suffer through Intel HD4000. It's abysmal performance-wise, especially with Yosemite's new effects.

Intel HD5000 is barely passable, but will be quickly rendered outdated by Haswell's integrated GPU.
 
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